A wear-resistant, self-healing and recyclable multifunctional waterborne polyurethane coating with mechanical tunability based on hydrogen bonding and an aromatic disulfide structure

Abstract

Considering a sustainable society, it is highly desirable to develop coatings that combine excellent wear-resistance, healing and recovery capabilities with tunable mechanical properties. Herein, a novel type of self-healing waterborne polyurethane (HSPU) film with dynamic quadrupolar hydrogen (UPy) and aromatic disulfide bonds was developed. The prepared HSPU films show nice mechanical properties and self-healing abilities. The introduction of UPy and aromatic disulfide bonds can significantly enhance the mechanical performance of HSPU films, and their highest tensile strength and elongation at break can reach 29.67 MPa and 991.8%, respectively. The HSPU films exhibit a great healing efficiency (95.1%) within 8 h at room temperature. As the healing temperature increases to 80 °C, the tensile strength of the HSPU film recovers to 98.6% within 30 min. Furthermore, the HSPU film can be reprocessed under pressure or recycled in solvent at room temperature. More importantly, HSPU-coated leather samples exhibit excellent wear resistance, and the self-healing treated leather samples after wear still show great wear resistance. This is mainly attributed to the synergistic effect of UPy and aromatic disulfide bonds, which break through the contradiction between the mechanical properties and self-healing properties of materials.